docs: def lookup_in(self, key, *specs, **kwargs):
          """Atomically retrieve one or more paths from a document.
  
          :param key: The key of the document to lookup
          :param spec: A list of specs (see :mod:`.couchbase.subdocument`)
          :return: A :class:`.couchbase.result.SubdocResult` object.
              This object contains the results and any errors of the
              operation.
  
          Example::
  
              import couchbase.subdocument as SD
              rv = cb.lookup_in('user',
                                SD.get('email'),
                                SD.get('name'),
                                SD.exists('friends.therock'))
  
              email = rv[0]
              name = rv[1]
              friend_exists = rv.exists(2)
  
          .. seealso:: :meth:`retrieve_in` which acts as a convenience wrapper
          """
          return super(Bucket, self).lookup_in({key: specs}, **kwargs)